The vessel of a reactor in a nuclear power plant is provided with a number of lead-through which, where necessary, are prepared for mounting of various sensors or equipment. A number of such lead-throughs are mostly not utilized and then usually closed and sealed by a conventional sealing flange.
After a period of one or a few operating seasons, active material, for example in the form of solid corrosion products, accumulates in these lead-throughs sealed by sealing flanges in such a quantity that a noticeable radiation level can be detected from them. This results in drawbacks, especially since the mentioned lead-throughs are usually arranged at the bottom of the reactor vessel close to, inter alia drive devices, on which maintenance is continuously being performed, so personnel are regularly present in the area around the lead-throughs sealed by sealing flanges.
Cleaning of a lead-through sealed by a sealing flange is admittedly possible, but must then be carried out by means of complex and difficult methods which, in addition, must be carried out from inside the reactor vessel. The object of the invention is to suggest a device intended to seal the lead-through which enables the lead-through, by means of a simple method, to be opened, washed clean and closed again.